Ship stabilizer apparatus



May 24, 1960 w. VANDERSTEEL SHIP STABILIZER APPARATUS L H m w v e R s Em mm .v E M O a WW w 8 A W 3 u w m a d v E 0%. 1:: E; 4 W H 7, Y m M d.m fin-I 3 Sheets-Sheet 2 W. VANDERSTEEL SHIP STABILIZER APPARATUS May24, 1960 Filed May 7, 1958 I N V E N 7'0? M4 4 MM Kama/P5 7554 3y TORNEYy 4, 1960 w. VANDERSTEEL 2,937,608

SHIP STABILIZER APPARATUS Filed May 7, 1958 3 Sheets-Sheet 3 Fin DownFlu up INVENTOR Mun/u klwpe sresz.

ATTORNEY tates SHIP STABILIZER APPARATUS William Vandersteel, BonnieHeights Road, Manhasset, N.Y.

Filed May 7, 1958, Ser. No. 733,660 9'Clain1s. (Cl. 114-126) atent Abilizers are referred to herein as activated fin stabilizers.

The present invention is particularly concerned with activated finstabilizers, although certain features of the invention have a broaderfield of utility.

Ship stabilizing apparatus of the laterally projecting activated fintype was first suggested many years ago, but only in recent years has itreached a stage of practical development. Activated fin type stabilizersare now in use on many large ocean vessels and are being installed in anever greater number. It is a necessary feature of any such stabilizingfin, that during times when its function is not needed, it beretractable into the hull of the vessel. Such retraction decreases hullresistance and also provides protection of the fin during maneuvering inharbors. One presently used retracting mechanism moves the fin endwiseinto a sea chest formed by suitable walls within the hull of the ship.Another known mechanism pivots the fin about a vertical axis, allowingthe fin to retract into a horizontal slot or recess in the hull. Both ofthe mechanisms just described are designed to provide a rigid supportfor the fin when it is extended in the operating position.

Considerable ditficulty has been encountered with the presentlyavailable commercial stabilizing fins because of breakage, andsubsequent loss of the fins in times of severe stress. This difficultyis inherent in a fin which is supported so as to be substantially rigidin its extended position. The breakage of fins during service conditionsmust be ascribed to their being subjected to overloads which cannot beproperly calculated or anticipated.

One object of the present invention is to provide apparatus of the typedescribed in which the fin mounting includes means for relieving thestresses imposed on the fin and its supporting structure under extremeoverload conditions.

Another object is to provide apparatus of the type described in whichthe space requirements within the hull for the retracted fin and itsoperating mechanism are reduced as compared to the correspondingrequirements of, the prior art devices.

Still another object of the invention is to provide a hinge-mounted finhavingthe hinge axis so disposed that the lift forces to which thefin issubjected create a moment about the hinge axis, which moment may beapplied to control the angle of attack of the fin.

The foregoing objects are attained in the preferred structures describedherein by providing a stabilizing fin which is retracted by rotationabout an axis extending horizontally fore and aft of the ship, so thatthe fin retracts, by movement in a vertical plane into a recess in theside of the hull. However, as will presently appear,

2,937,608 Patented May 24, 1960 ice the disposition of the hinge axismay be other thanhorizontal provided that it is at an angle to avertical, athwartship plane, whereby the lift forces encountered by thefin create a moment tending to rotate the fin bodily about its hingeaxis. As will be understood, such moment is a maximum when the'hingeaxis is horizontal or, in other words, is at 90 to the vertical,athwart-ship plane. Suitable operating mechanism is provided formaintaining the fin in the extended operating position and forretraction of the fin. By incorporating resilient means in thatmechanism, the fin is given a controlled degree of freedom to deflect upor down in the event it is subjected to loading in excess of its designcapacity. The resilient means may be so designed as to maintain the finnormally in a stable angular position with' respect to the retractingaxis and to deflect from that position only when subjected to anoverload.

The operating mechanism for retracting and extending the fin includingthe resilient means to provide strain relief are preferably situatedinboard and may take a variety of forms, one of which is describedherein.

The fin mounting includes a main shaft on which the fin turns forretraction and extension. This shaft is supported by two bearingslocated inboard and on respectively opposite sides of the fin Attachedto each end of the main shaft are two crank arms which in turn areconnected through strain relief devices to a motor means for moving thearms to retract and extend the fins. The strain relief devicesresiliently hold the fin in the extended position and permit the fin todeflect from that position under conditions of excessive stress.

Other objects and advantages of the invention become apparent from aconsideration of the following specification and claims taken togetherwith the accompanying drawings.

In the drawings:

Fig. l is a horizontal sectional view through the hull of a vessel,showing a stabilizing fin and operating mechanism therefor in accordancewith one form of the present invention, with the fin in its stabilizingposition, part of the operating mechanism being shown in section;

Fig. 2 is a vertical section on the line 2-2 of Fig. 1.

Fig. 3 is a schematic view corresponding generally to Fig. l 'butshowing a modified form and application of the invention.

' Referring now to Figs. 1 and 2 of the drawings, there is shown a fin 1having a flap 2 pivotally mounted along its trailing edge. bolts 3 onthe end of a cross shaft 4 which is journaled for rotation about itslongitudinal axis in a yoke or housing 5. The housing 5, together withprojecting trunnions 5a, forms a main or hinge shaft, generallyindicated at 6, journaled in bearing'blocks 7 fixed to the frame of theship. The housing 5 is located inside of the wall of a sea chest 8,which extends vertically upward as shown in Fig. 2 and is adapted toreceive the fin 1, when the latter moves to its retracted position,shown in dotted lines in Fig. 2.

Two bearings 9 and 10 support the cross shaft 4 within the housing 5. Aseal ring 11 on the housing 5 engages a fiat face on a flange on theshaft 4, thereby sealing the housing against the entrance of sea water.A pair of seal rings, one of which is shown at 12, are mounted'on therespective bearing blocks 7 and engage flat faceson the housing 5,thereby sealing the wallsof the sea chest against the leakage of seawater. These seals are shown somewhat diagrammatically and may be of anysuitable construction for use with relatively rotating surfaces. Notethat neither of the seals is required to'seal between two relativelysliding cylindrical members as is the case in certain of' the shipstabilizers of the prior art. The seal structures used may therefore beconsiderably simpler The fin 1 is mounted by means of 3 and are alsomore effectively than is the case with the socalled sliding fit seals.

The trunnions 5a project through the opposite sides of the bearingblocks 7 from'the wall of the sea chest. On the respective ends of thetrunnions 5a, there are fixed, as by keying, a pair of crank arms 13.The opposite ends of the crank arms 13 are connected by pivot pins 20 tothe ends of a pair of strain relief links generally indicated by thereference numeral 14.

Each strain relief link 14 (see Fig. 2) comprises a cylinder 15 pivotedby a pin 16 to a cross head 17. A piston 18 runs within the cylinder 15and is provided with an aperture 18a extending between its two ends.

The piston 18 is biased to the center of cylinder 15 by a pair ofopposed coil springs 31 and 32. The cylinder is filled with oil or othersuitable hydraulic fluid. The piston 18 is fixed on a piston rod 19pivoted at 20 to the outer end of one of the arms 13.

The cross-head 17 is apertured to receive rotatably an internallythreaded sleeve which projects upwardly beyond the upper face of thecross-head 17 and carries on its outer periphery at that point a wormgear 25. The worm gear 25 mates with a worm 24 driven by a motor 26mounted on a bracket 17a attached to the cross-head 17 and supplied withelectrical energy from any suitable source. The worm gear 25 and itssleeve turn on a threaded fixed column 21, so that as the motor 26 runsthe cross-head 17 is raised or lowered, thereby rotating shaft 6 andextending or retracting the fin 1.

The shaft 4 has mounted on its inner end a hydraulic servo-motor 27enclosed in a cap 28 on the end of housing 5. The servo-motor 27 issupplied with hydraulic fluid from any suitable system through passages29 and 30 drilled in the respective trunnions 5a and opening into portsinside the housing 5. By supplying hydraulic fluid to one or the otherof the passages 29 and 30 by way of lines 31 or 32 and connecting theother line to a drain, the motor 27 may be rotated in either direction,as desired, to change the angle of attack of the fin 1.

The positioning of the flap 2 relative to flap 1 is well known in theart, and is used to reduce the angle through which the fin 1 must betilted in order to achieve a desired stabilizing effect.

When the fin 1 is in its active or stabilizing position, which is shownin full lines in Fig. 2, it is effective, when the ship tends to roll,to apply to the water a thrust which is resisted by the water, therebytending to reduce the rolling action. The upward or downward thrust onthe fin 1 is translated into a torque tending to rotate the fin aboutthe axis of the main shaft 6.

When the fin 1 tends to rotate about the hinge shaft 6, that rotation isopposed by one of the springs 31 and 32, depending upon the particulardirection of rotation, and by the viscosity of the hydraulic fluid inthe cylinder 15, which must flow through the passage 18a in order forthe piston 18 to move relative to the cylinder 15. By selecting thesprings 31 and 32 with a substantial spring rate, any movement of thefin 1 from its normal position may be prevented until the torque on thefin 1 exceeds a value suflicient to start compressing one of thesprings. The piston 18 thereupon moves in the cylinder 15 allowing thefin 1 to pivot upwardly or downwardly from its normal position. Themaximum deflection of the fin 1 from its active stabilizing position isdetermined by the construction of the strain relief link 14. In thearrangement shown, that deflection is determined by the points at whichthe springs 31 and 32 go solid, i.e., the position.

where their turns abut against each other. It is preferred to have thisposition reached when the fin 1 deflects approximately 20 in eitherdirection from its nor mal stabilizing position. Such an arrangementeffectively reduces the maximum forces to which the fin 1 and itssupporting mechanism are subjected.

After the deflecting torque ceases, the springs 31 and 32 are effectiveto restore the piston 18 to its normal position at the center of thecylinder, and thereby to restore the fin to its normal position.

When it is desired to retract the stabilizer, the motor 26 isoperatedrto run the parts to the position shown in dotted lines in Fig.2, wherein the fin 1 lies within the sea chest 8. There is then no partof the stabilizer mechanism extending beyond the outline of the shipshull. It may be observed that the volume of sea chest required tocontain the stabilizing apparatus within the outlines of the hull is ofa minimum size, and presents no interference to the ships framing.Furthermore, most of the operating mechanism may be supported close tothe sea chest, so that the space required within the ships hull for theentire apparatus is minimized.

In the Fig. 3 form of the invention, the parts having the same structureand function as those already described bear primed reference charactersand require no further description (it being understood, of course, thatthe fin of Fig. 3 is mounted in a hull sea chest and is retractable intoit, just as in the showing of Figs. 1 and 2).

In this form, a modified strain relief arrangement is indicated, piston35 operating in a cylinder 36, which is filled with oil or othersubstantially incompressible fluid medium, the opposite ends of whichcylinder are provided with spring-loaded relief valves 37, which aredesigned to blow at a predetermined limit pressure.

Furthermore, the Fig. 3 showing illustrates an extended application ofthe invention in which the lift forces encountered by the fin areutilized to effect changes in the angle of attack of the fin.

Provided the fin hinge axis is appropriately disposed, it will be seenthat water action creating lift forces (so characterized in this artwhether the net water action be upward or downward) will create a momentabout the hinge axis of the fin; that is, they will tend to rotate thefin bodily about its hinge axis, such moment normally being counteractedby the strain relief means as above described. As will be apparent, too,such a moment is created not only when the hinge axis is disposed hon'-zontally in a fore and aft plane as illustrated, but whenever the axisis other than aligned with the line of action of the lift forces.Assuming the net lift forces to act substantially vertically, it isobvious that the moment is zero if the hinge axis of the fin is disposedin a vertical, athwart-ship plane, the moment increasing as the hingeaxis is tilted fore-and-aft with respect to such a plane and reachingthe maximum when the axis is disposed horizontally, as shown.

While this feature of the invention lends itself to embodiment in agreat variety of forms, a schematic showin of one simplified form onlyis illustrated.

According to this showing, the upper and lower ends of cylinder 36 areconnected by flexible tubes 40, 41 (of very small cross section comparedto that of cylinder 36) to the opposite ends of a servo cylinder 42housing a piston 43 the movement of which is opposed by suitable springs44, 45. By this means, the lift forces sensed by the fin are translated,as a function of increased oil pressure at one end or the other ofcylinder 36, to change the position of piston 43 in its cylinder 42.

The rod 46 of piston 43 is connected to the upper end of a so-calledhunting rod 50, the lower end of which is connected by rod 51 to theship motion sensing device indicated at 52. Such a device is well-knownin the art and since, per se, it forms no part of the present invention,it requires no detailed description. The function of the sensing device,of course, is to dictate the lift requirement of the fin in accordancewith the usual gyro and other data supplied to it.

Intermediate its ends, the hunting rod is connected by rod 53 to thecontrol crank 54 of the fin tilting apparatus 55, that is, the apparatuswhich serves to change the angle of attack of the fin, as directed byand in accordance with the movement of the mid-point of the hunting rod.This apparatus, again, may be of any well-known or preferred form butfor present purposes, 55 may be assumed to comprise a variabledisplacement hydraulic pump serving to supply hydraulic fluidunderpressure to line 31 or line 32' and at a varying rate, dependingupon the disposition of control crank 54.

Thus, regardless of the position of the hunting rod as dictated by thesensing device 52, the servo mechanism 42-46, responsive to the momentcreated by the action of the lift forces on the hinged fin, isefi'ective to control the means for changing the angle of attack of thefin, in this instance the pump means 55.

In the light of the foregoing exemplification of the principles of theinvention, the following is claimed:

1. Apparatus for stabilizing a ship against rolling, comprising a fin, amain shaft supporting said fin and rotatable about an axis extendingparallel to the ship's side and just inside the hull, said shaft and finbeing movable between an operating position wherein the fin projectslaterally from the hull and is subjected to torque about said axis whenthe ship tends to roll, and a retracted position wherein the fin extendsparallel to the hull, motor means, means connecting said motor means tosaid shaft for rotating it between its operating and retractedpositions, strain relief means in said connecting means to permitlimited angular motion of said shaft under the influence of said torquewithout moving said motor means, a housing fixed on said main shaft, anda cross shaft journaled in said housing and carrying said fin forrotation about an axis extending at right angles to said main shaft.

2. Ship stabilizing apparatus as defined in claim 1, including bearingmeans in said housing supporting said cross shaft, and rotary seal meansprotecting said bearing means against the entrance of sea water.

3. Ship stabilizing apparatus as defined in claim 2, including a fluidservo-motor in said housing to rotate said cross shaft and fluid supplylines extending to said servomotor, through said main shaft and saidhousing.

4. Apparatus for stabilizing a ship against rolling, comprising a fin, amain shaft supporting said fin and rotatable about an axis extendingsubstantially parallel to the ships side and just inside the hull, saidfin and shaft being movable between an operating position wherein thefin projects laterally from the hull and is subjected to torque aboutsaid axis when the ship tends to roll, and a retracted position whereinthe fin extends parallel to the hull, walls defining a seat chest insidethe outline of the hull to receive the retracted fin, said shaftprojecting through the walls of said sea chest, rotary seal meansbetween said shaft and said walls, motor means, means connecting saidmotor means to said shaft for rotating it between its operating andretracted positions, said connecting means comprising crank arms on theshaft inside the hull, and strain relief means in said connecting meansto permit limited angular motion of said shaft under the influence ofsaid torque without moving said motor means.

5. Apparatus for stabilizing a ship against rolling, comprising a fin, amain shaft supporting said fin and rotatable about an axis extendingparallel to the ships side and just inside the hull, said shaft and finbeing movable between an operating position wherein the fin projectslaterally from the hull and is subjected to torque about said axis whenthe ship tends to roll, and a retracted position wherein the fin extendsparallel to the hull, motor means, means connecting said motor means tosaid shaft for rotating it between its operating and retractedpositions, strain relief means in said connecting means to permitlimited angular motion of said shaft under the infiuence of said torquewithout moving said motor means, a housing fixed on said main shaft, across shaft journaled in said housing and carrying said fin for rotationabout an axis extending at right angles to said main shaft, means insaid housing for applying torque to said cross shaft, walls defining asea chest inside the outline of the hull to receive the retracted fin,said main shaft projecting through the Walls of said sea chest, rotaryseal means between the main shaft and said walls, said main shaft havingapertures extending therethrough from inside the hull through said wallsand communicating with the interior of said housing, and means extendingthrough said apertures and controllable from inside the hull foractuating said torque applying means.

6. In a ship stabilizer apparatus of the kind including a fin, a finshaft supporting the same and power means for rocking the fin about theaxis of its support shaft and thereby changing the angle of attack ofthe fin, the improvement which comprises hinge support means for thesaid fin and fin shaft adapted to permit bodily movement of the fin andthe fin shaft about the axis of the hinge support means, the hinge axisbeing so positioned that the lift forces acting on the fin create amoment about such axis, and transmission means for applying such momentto activate the said power means and thereby rock the fin about thefirst-mentioned axis.

7. In a ship stabilizer apparatus of the kind including a fin, a finshaft supporting the same and power means for rocking the fin about theaxis of its support shaft and thereby changing the angle of attack ofthe fin, the im provement which comprises hinge support means for thesaid fin and fin shaft adapted to permit bodily movement of the fin andshaft about the hinge axis of the support means, the hinge axis being sopositioned that the lift forces acting on the fin create a moment aboutsuch axis, and transmission means for applying such moment to activatethe said power means and thereby rock the fin about thecfirst-mentionedaxis, said transmission means including yieldable means normallyrestraining the fin and shaft against bodily movement about the saidhinge axis.

8. In a ship stabilizer apparatus of the kind including a fin, meansmounting the same for rotation about a laterally projecting axis forvarying the angle of attack of the fin, thereby to create roll-reducingthrust, and power means for rotating the fin about its said laterallyprojecting axis, the improvement which comprises hinge support means forthe said fin adapted to permit bodily movement thereof about a secondaxis, the latter being disposed at an angle to a vertical athwart-shipplane, whereby the lift forces encountered by the fin create a momenttending to rotate the fin bodily about the said second axis, andtransmission means for applying such moment to activate the said powermeans and thereby rotate the fin about the laterally projecting axis.

9. In a ship stabilizer apparatus of the kind including a fin, meansmounting the same for rotation about a laterally projecting axis forvarying the angle of attack of the fin, thereby to create roll-reducingthrust, and power means for rotating the fin about its said laterallyprojecting axis, the improvement which comprises hinge support means forthe said fin adapted to permit bodily movement thereof about a secondaxis, the latter being disposed horizontally in a fore and aft plane,whereby the lift forces encountered by the fin create a moment tendingto rotate the fin bodily about the said second axis, and transmissionmeans for applying the said moment to activate the said power means andthereby rotate the fin about the laterally projecting axis.

References Cited in the file of this patent UNITED STATES PATENTS2,223,562 Giliberty Dec. 3, 1940

